Fixes bug 72348 "Page load performance slower in 0.8.1 than under 0.8"

r/sr=dougt,brendan

netwerk/base/src/nsStreamListenerProxy.cpp

@@ -176,6 +176,12 @@ nsOnDataAvailableEvent::HandleEvent()
             rv = NS_ERROR_NOT_IMPLEMENTED;
         }
 
+        // Cancel the request on unexpected errors
+        if (NS_FAILED(rv) && (rv != NS_BASE_STREAM_CLOSED)) {
+            LOG(("OnDataAvailable failed [rv=%x] canceling request!\n"));
+            mRequest->Cancel(rv);
+        }
+
         //
         // Update the listener status
         //

netwerk/base/src/nsStreamObserverProxy.cpp

@@ -122,7 +122,12 @@ nsOnStartRequestEvent::HandleEvent()
         return NS_ERROR_FAILURE;
     }
 
-    return observer->OnStartRequest(mRequest, mContext);
+    nsresult rv = observer->OnStartRequest(mRequest, mContext);
+    if (NS_FAILED(rv)) {
+        LOG(("OnStartRequest failed [rv=%x] canceling request!\n", rv));
+        mRequest->Cancel(rv);
+    }
+    return rv;
 }
 
 //